(i) Technical Field
The present invention relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus.
(ii) Related Art
Electrophotographic image forming apparatuses enable high-speed and high-quality printing and are therefore applied to image forming apparatuses such as copying machines and laser beam printers. The mainstream of electrophotographic photoreceptors used in image forming apparatuses is an organic photoreceptor containing an organic photoconductive material. In general production of the organic photoreceptor, for example, an undercoat layer (also referred to as “intermediate layer”) is formed on a conductive substrate, such as an aluminum substrate, and then a photosensitive layer is formed thereon.
In an example of known processes for producing a conductive substrate, for example, the peripheral surface of a cylindrical tube produced by extruding and subsequent drawing is subjected to machining to adjust, for instance, the thickness and surface roughness thereof.
A known process for producing a thin metal container in large quantities at low production costs is impact pressing in which slag placed on a die (female die) is formed into a cylinder by being punched with impact. The edge surface of the cylindrical product produced by the impact pressing is removed, so that a conductive substrate that can be used in electrophotographic photoreceptors (also referred to as “impact-pressed tube” or “IP tube”) can be produced at low cost.
Alternatively, another type of conductive substrate that can be used in electrophotographic photoreceptors can be produced merely by extruding and subsequent drawing such as cold drawing (also referred to as “drawn tube” or “ED tube”).